 #define _CRT_SECURE_NO_WARNINGS 1

class Solution
{
public:
	int combinationSum4(vector<int>& nums, int target)
	{
		vector<double> dp(target + 1);
		dp[0] = 1;
		for (int i = 1; i <= target; i++)
			for (auto x : nums)
				if (x <= i) dp[i] += dp[i - x];
		return dp[target];
	}
};